Studies are being carried out on primary cultures of astrocytes and on several transformed glial cell lines in vitro. Primary astrocytes are derived from neonatal rats, and other cell lines were derived from rodents either by viral transformation of primary cutures (TRPG, S22) or from tumors induced in situ and subsequently established in cell culture (C6, B9, B82). The levels of key metabolites, glucose, lactate, pyruvate, ATP, P-creatine, GABA, glutamate and cyclic nucleotides were measured in cells and medium after refeeding confluent cells with MEM plus glucose. Primary astrocytes, HSV-1 transformants derived from primary astrocytes (TRPG) and C6 cells all show a rapid increase in glucogen content after refeeding, while other glial cell lines, B9, B82 and S22, synthesize relatively low levels of glucose. The various lines have been examined for a cyclic nucleotide response to beta-adrenergic agonists, purinergic agonists and others. All cell lines examined to date exhibit a response to adrenergic stimulation, but only the primary astrocytes exhibit a response to adenosine or adenosine analogs.